Abstract There is currently sparse research on the effects of cannabis use on psychomotor function [4] despite the impact of cannabis on cortico-striatal networks critical for both cognition and motor performance and the impact of psychomotor deficits on activities of daily living. The scientific premise of this proposal is based on emerging evidence suggesting that cannabis use has detrimental effects on the ability to perform coordinated movements that result in impaired motor control. Because performance of coordinated movements hinge on the ability to learn motor skills, we will test the hypothesis that cannabis users also have impaired motor learning. The overarching goal of this study is to understand how cannabis use may impact motor learning and determine how it is related to critical functions such as memory and motor performance. To that end, we will: (1) examine whether motor learning deficits are observable in cannabis users during ad libitum use and abstinence (Aim 1) and (2) investigate the unique contributions of cognitive and motor performance on motor learning in cannabis users to identify treatment targets (Aim 2) by using a mediation analysis model. We will use a modified version of the SRT task during EEG along with a battery of behavioral and cognitive assessments to understand the impact of cannabis use on motor impairments in adult cannabis users during ad libitum use and 3-day abstinence compared to age- and sex-matched non-using controls. Participants will be characterized on behaviors related to cannabis use, motor learning (via SRT task during EEG) and cognitive functions. Motor learning is critical for daily functioning; thus, determining the mechanisms that underlie deficits in motor learning and performance as a result of cannabis use can advance cognitive motor research in addiction, inform rehabilitative strategies, and guide changes in policy surrounding cannabis use particularly in areas that rely on motor performance. The results from this research will have wide implications not just in addiction and motor neuroscience, but also public health and safety.